(CNN) -- Iran reportedly plans next week to put on trial seven Baha'i prisoners accused of espionage, even though one of their lawyers has become a fellow detainee and the other is outside the country.

The death penalty trial was delayed from last month and now human rights activists are concerned that closed-door proceedings without the lawyers will result in a judicial farce.

Diane Ala'i, the Baha'i International Community's representative to the United Nations in Geneva, Switzerland, said the trial date became known after Iranian authorities sent a notice to Abdolfattah Soltani, a human rights lawyer who was arrested in the aftermath of Iran's disputed June 12 presidential election.

The writ of notification, dated July 15, sets a trial date for August 18, Ala'i said: "It is the height of absurdity to issue a trial notice to a lawyer who has himself been unjustly imprisoned," she said.

Soltani, a well-known human rights lawyer, is affiliated with the Tehran-based Defenders of Human Rights Center, founded by Nobel Peace Prize laureate Shirin Ebadi. It took up the case of the seven Baha'is last year.

The International Campaign for Human Rights in Iran said Soltani was detained along with other human rights activists in the post-election turmoil and is behind bars at Evin, the same prison where the Baha'is are incarcerated. Ebadi was on a speaking tour when Soltani was arrested and has not returned to Iran.

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The Baha'is are accused of spying for Israel, spreading propaganda against the Islamic Republic and committing religious offenses -- allegations that Ala'i said are "completely false." "The trial is all about them being Baha'i," she said.

The Baha'i faith originated in 19th-century Persia, but modern-day Iran does not recognize it, though it denies any mistreatment of members of the largest non-Muslim religious minority.

The International Campaign for Human Rights in Iran, however, has reported an intensified persecution of Baha'is in recent years, including cemetery desecration, arbitrary detention, home raids, property confiscation, work expulsion and denial of basic civil rights.

The case of the seven Baha'is has drawn global attention. Roxana Saberi, the Iranian-American journalist freed from Evin prison earlier this year, spoke on their behalf, as have Human Rights Watch and the U.S. Commission on International Religious Freedom (USCIRF).

"We continue to call on the White House and State Department to condemn the imprisonment of the seven innocent Baha'is and demand their immediate and unconditional release," said Leonard Leo, chairman of USCIRF, which is an independent bipartisan federal commission.

"The Iranian government should live up to its international human rights commitments and permit the more than 300,000 Baha'is in Iran to practice their faith peacefully, rescind any existing laws that permit members of the Baha'i faith to be killed with impunity, and allow full access for Baha'is to study in public universities without discrimination," he said.

Ala'i said the investigation into the charges against the prisoners concluded months ago, but Iran has continued to hold them in Evin prison without access to their lawyers and with minimal contact with their families.

They were under solitary confinement the first five months after their incarceration. Six were arrested in May 2008 at their Tehran homes; one was arrested in the eastern city of Mashad in March 2008.

The upcoming trial, without the presence of the two key lawyers, amounts to another tactic to deprive the prisoners of their legal rights, Ala'i said. She called it a "travesty of justice."

She also said the August 18 trial date could change, noting that the families of the seven had been told in June that they were to be tried on July 11, only to have that date come and go.

"Given the past history of this case, the utter lack of concern for procedure on the part of authorities, and the current situation in Iran, it is simply not possible to know when the proceedings will actually begin," she said.